[1] Baueг F.: A note on uniqueness and convergence of successive approximations. Canad. Math. Bull. 2 (1959), 5-8. MR 0103309

[2] Brauer F.: Some results on uniqueness and successive approximations. Canad. J. Math. 11 (1959), 527-533. MR 0108603 | Zbl 0142.34305

[3] Kpacнoceльcкий M. A., Kpeйн C. Г.: О6 oднoм клacce meopeм eдuнcmeeннocmu для ypaвнeнuя $y' = f(x, y)$. Уcпexи мaтeм, нayк 11 (1965), 209-213.

[4] Palczewski B.: On the uniqueness of solutions and the convergence of successive approximations in the Darboux problem under the conditions of the Krasnosielski and Krein type. Ann. Polon. Math. 14 (1964), 183-190. MR 0161014 | Zbl 0132.07301